<html><head></head><body><div style="font-family: Verdana;font-size: 12.0px;"><div>I see. This would work if the matrices are on different subcommumicators ? Is it possible to add this functionality ?</div>
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<div>marius</div>
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<div>You basically need the inverse of MatCreateSubmatrices(). I do not think we have that right now, but it could probably be done without too much trouble by looking at that code.
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<div> Thanks,</div>
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<div> Matt</div>
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<div class="gmail_attr">On Tue, Feb 19, 2019 at 6:15 AM Marius Buerkle via petsc-users <<a href="mailto:petsc-users@mcs.anl.gov" onclick="parent.window.location.href='mailto:petsc-users@mcs.anl.gov'; return false;" target="_blank">petsc-users@mcs.anl.gov</a>> wrote:</div>
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<div>Hi !</div>
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<div>Is there some way to combine MatCompositeMerge with MatCreateRedundantMatrix? I basically want to create copies of a matrix from PETSC_COMM_WORLD to subcommunicators, do some work on each subcommunicator and than gather the results back to PETSC_COMM_WORLD, namely I want to sum the the invidual matrices from the subcommunicatos component wise and get the resulting matrix on PETSC_COMM_WORLD. Is this somehow possible without going through all the hassle of using MPI directly? </div>
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<div>marius</div>
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<div>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br/>
-- Norbert Wiener</div>
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<div><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank">https://www.cse.buffalo.edu/~knepley/</a></div>
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